Limits...
Nicotinamide mononucleotide, an intermediate of NAD+ synthesis, protects the heart from ischemia and reperfusion.

Yamamoto T, Byun J, Zhai P, Ikeda Y, Oka S, Sadoshima J - PLoS ONE (2014)

Bottom Line: The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1.The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway.In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America.

ABSTRACT
Nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme for nicotinamide adenine dinucleotide (NAD+) synthesis, and Sirt1, an NAD+-dependent histone deacetylase, protect the heart against ischemia/reperfusion (I/R). It remains unknown whether Nampt mediates the protective effect of ischemic preconditioning (IPC), whether nicotinamide mononucleotide (NMN, 500 mg/kg), a product of Nampt in the NAD+ salvage pathway, mimics the effect of IPC, or whether caloric restriction (CR) upregulates Nampt and protects the heart through a Sirt1-dependent mechanism. IPC upregulated Nampt protein, and the protective effect of IPC against ischemia (30 minutes) and reperfusion (24 hours) was attenuated at both early and late phases in Nampt +/- mice, suggesting that Nampt plays an essential role in mediating the protective effect of IPC. In order to mimic the effect of Nampt, NMN was administered by intraperitoneal injection. NMN significantly increased the level of NAD+ in the heart at baseline and prevented a decrease in NAD+ during ischemia. NMN protected the heart from I/R injury when it was applied once 30 minutes before ischemia or 4 times just before and during reperfusion, suggesting that exogenous NMN protects the heart from I/R injury in both ischemic and reperfusion phases. The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1. Compared to control diet (90% calories), CR (60% calories for 6 weeks) in mice led to a significant reduction in I/R injury, accompanied by upregulation of Nampt. The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway. In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

Show MeSH

Related in: MedlinePlus

NMN stimulates autophagy in control hearts.A, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to Tg-mRFP-GFP-LC3 mice. After 2 hours, the number of fluorescent LC3 dots was evaluated. Representative images of GFP puncta, mRFP puncta and their merged images are shown. The results of the quantitative analysis of RFP only dots and RFP/GFP double positive (yellow) dots/area are also shown. B, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to mice 30 minutes before I/R, and then the mice were subjected to either 30 minutes ischemia followed by 24 hours of reperfusion or sham operation. The extent of cardiomyocyte apoptosis in the border zone was evaluated with TUNEL staining. The results of the quantitative analysis of TUNEL-positive cardiomyocytes are shown. C. Three days after isolation, cardiomyocytes were treated with the indicated dosage of NMN for 30 minutes (Left) and with 1000 nM NMN for the indicated time (Right). ATP contents were measured by ATP Bioluminescent Assay Kit (Sigma). n = 4 (Left) and 3(Right).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4048236&req=5

pone-0098972-g007: NMN stimulates autophagy in control hearts.A, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to Tg-mRFP-GFP-LC3 mice. After 2 hours, the number of fluorescent LC3 dots was evaluated. Representative images of GFP puncta, mRFP puncta and their merged images are shown. The results of the quantitative analysis of RFP only dots and RFP/GFP double positive (yellow) dots/area are also shown. B, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to mice 30 minutes before I/R, and then the mice were subjected to either 30 minutes ischemia followed by 24 hours of reperfusion or sham operation. The extent of cardiomyocyte apoptosis in the border zone was evaluated with TUNEL staining. The results of the quantitative analysis of TUNEL-positive cardiomyocytes are shown. C. Three days after isolation, cardiomyocytes were treated with the indicated dosage of NMN for 30 minutes (Left) and with 1000 nM NMN for the indicated time (Right). ATP contents were measured by ATP Bioluminescent Assay Kit (Sigma). n = 4 (Left) and 3(Right).

Mentions: We also investigated the effect of NMN upon autophagy in the heart by treating mRFP-GFP-LC3 mice with NMN. Autophagic puncta were evaluated 2 hours after NMN treatment. Both autophagosomes, indicated by red and green puncta shown as yellow puncta in merged images, and autolysosomes, indicated by red puncta, were increased in response to NMN treatment (Figure 7A), suggesting that NMN stimulates autophagy. This is consistent with our previous observations that both Nampt and Sirt1 promote autophagy in cardiomyocytes [13], [16]. Furthermore, NMN significantly reduced the number of TUNEL- positive cardiomyocytes in the peri-infarct area after I/R (Figure 7B). NMN did not significantly affect the level of ATP in mitochondria (Figure 7C). Taken together, these results suggest that NMN may protect the heart through stimulation of autophagy during myocardial ischemia and consequent suppression of cardiomyocyte apoptosis.


Nicotinamide mononucleotide, an intermediate of NAD+ synthesis, protects the heart from ischemia and reperfusion.

Yamamoto T, Byun J, Zhai P, Ikeda Y, Oka S, Sadoshima J - PLoS ONE (2014)

NMN stimulates autophagy in control hearts.A, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to Tg-mRFP-GFP-LC3 mice. After 2 hours, the number of fluorescent LC3 dots was evaluated. Representative images of GFP puncta, mRFP puncta and their merged images are shown. The results of the quantitative analysis of RFP only dots and RFP/GFP double positive (yellow) dots/area are also shown. B, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to mice 30 minutes before I/R, and then the mice were subjected to either 30 minutes ischemia followed by 24 hours of reperfusion or sham operation. The extent of cardiomyocyte apoptosis in the border zone was evaluated with TUNEL staining. The results of the quantitative analysis of TUNEL-positive cardiomyocytes are shown. C. Three days after isolation, cardiomyocytes were treated with the indicated dosage of NMN for 30 minutes (Left) and with 1000 nM NMN for the indicated time (Right). ATP contents were measured by ATP Bioluminescent Assay Kit (Sigma). n = 4 (Left) and 3(Right).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048236&req=5

pone-0098972-g007: NMN stimulates autophagy in control hearts.A, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to Tg-mRFP-GFP-LC3 mice. After 2 hours, the number of fluorescent LC3 dots was evaluated. Representative images of GFP puncta, mRFP puncta and their merged images are shown. The results of the quantitative analysis of RFP only dots and RFP/GFP double positive (yellow) dots/area are also shown. B, Either NMN (500 mg/kg per injection) or vehicle (PBS) was administered (i.p. injection) to mice 30 minutes before I/R, and then the mice were subjected to either 30 minutes ischemia followed by 24 hours of reperfusion or sham operation. The extent of cardiomyocyte apoptosis in the border zone was evaluated with TUNEL staining. The results of the quantitative analysis of TUNEL-positive cardiomyocytes are shown. C. Three days after isolation, cardiomyocytes were treated with the indicated dosage of NMN for 30 minutes (Left) and with 1000 nM NMN for the indicated time (Right). ATP contents were measured by ATP Bioluminescent Assay Kit (Sigma). n = 4 (Left) and 3(Right).
Mentions: We also investigated the effect of NMN upon autophagy in the heart by treating mRFP-GFP-LC3 mice with NMN. Autophagic puncta were evaluated 2 hours after NMN treatment. Both autophagosomes, indicated by red and green puncta shown as yellow puncta in merged images, and autolysosomes, indicated by red puncta, were increased in response to NMN treatment (Figure 7A), suggesting that NMN stimulates autophagy. This is consistent with our previous observations that both Nampt and Sirt1 promote autophagy in cardiomyocytes [13], [16]. Furthermore, NMN significantly reduced the number of TUNEL- positive cardiomyocytes in the peri-infarct area after I/R (Figure 7B). NMN did not significantly affect the level of ATP in mitochondria (Figure 7C). Taken together, these results suggest that NMN may protect the heart through stimulation of autophagy during myocardial ischemia and consequent suppression of cardiomyocyte apoptosis.

Bottom Line: The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1.The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway.In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America.

ABSTRACT
Nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme for nicotinamide adenine dinucleotide (NAD+) synthesis, and Sirt1, an NAD+-dependent histone deacetylase, protect the heart against ischemia/reperfusion (I/R). It remains unknown whether Nampt mediates the protective effect of ischemic preconditioning (IPC), whether nicotinamide mononucleotide (NMN, 500 mg/kg), a product of Nampt in the NAD+ salvage pathway, mimics the effect of IPC, or whether caloric restriction (CR) upregulates Nampt and protects the heart through a Sirt1-dependent mechanism. IPC upregulated Nampt protein, and the protective effect of IPC against ischemia (30 minutes) and reperfusion (24 hours) was attenuated at both early and late phases in Nampt +/- mice, suggesting that Nampt plays an essential role in mediating the protective effect of IPC. In order to mimic the effect of Nampt, NMN was administered by intraperitoneal injection. NMN significantly increased the level of NAD+ in the heart at baseline and prevented a decrease in NAD+ during ischemia. NMN protected the heart from I/R injury when it was applied once 30 minutes before ischemia or 4 times just before and during reperfusion, suggesting that exogenous NMN protects the heart from I/R injury in both ischemic and reperfusion phases. The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1. Compared to control diet (90% calories), CR (60% calories for 6 weeks) in mice led to a significant reduction in I/R injury, accompanied by upregulation of Nampt. The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway. In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

Show MeSH
Related in: MedlinePlus